1. Field of the Invention
This invention relates to an ink jet recording head maintenance apparatus and more particularly to a maintenance apparatus of an ink jet recording head which ejects drops of ink drops through a nozzle provided in a nozzle plate, and an ink jet recording apparatus having the maintenance apparatus.
2. Discussion of the Background
There has been in widespread use an ink jet recording apparatus which performs printing by selectively ejecting ink drops to a recording medium from a plurality of nozzles arranged in a nozzle plate. In such an ink jet recording apparatus, the ink is likely to remain around the nozzles after the ejection of ink drops. The ink thus remaining, if dried/solidified, will cause deviation of direction of ink ejection or blocking of nozzles, and accordingly, defective ink ejection and defective printing are easy to occur. Furthermore, foreign substances such as dusts on the recording medium and dusts in the air will attach around the nozzles, similarly causing the deviated direction of ink ejection and the blocked nozzles to consequently result in the defective ink ejection and defective printing.
Therefore, there have been conventionally proposed various kinds of ink jet recording apparatus designed to remove ink or foreign substances remaining around the nozzles. For example, there has been proposed the technology that, with a wiping member formed of an elastic material or other pressed against the nozzle plate (a nozzle face of the nozzle plate), the wiping member is slid on the nozzle plate in this state to thereby wipe off the foreign substances holding on the nozzle plate. Furthermore, in Japanese Unexamined Patent Publications No. 2001-219567 and No. 2002-283590, there has been disclosed the technology that an improved adhering substance wiping effect is achieved by using a single wiping member at an increased wiping frequency. Furthermore, to achieve the adhering substance wiping effect, there has been disclosed the technology in Japanese Unexamined Patent Publication No. 2000-127417 that a groove is formed in a single wiping member to enable adjusting the angle of contact of the wiping member in relation to the nozzle face by utilizing the elastic deformation of the wiping member.
Furthermore, in Japanese Unexamined Patent Publication No. Hei 9-76517, there has been disclosed the technology that the optimum wiping effect is gained by setting the rubber hardness of a single wiping member within the range of 40 to 60 degrees of A Hardness specified in JIS K6301. Furthermore, to ensure the same wiping force of the wiping member notwithstanding a change in a distance between the recording head and the recording medium, a technology is disclosed that has achieved the wiping effect by the optimum arrangement of a plurality of wiping members of different free length and thickness so that the amount of deflection of the wiping member and the angle of contact of the wiping member with the nozzle face will vary in synchronization with a change in a distance between the recording head and the recording medium, in Japanese Unexamined Patent Publication No. 2000-177113.
The single wiping member, however, sometimes fails to properly function in response to a change in the kind of adhering substances (ink, fine particles of paper, dusts, etc.) or change in the substance conditions (e.g., an increase in ink adhesion caused by environmental changes, and an increase in ink adhesion by the length of time when ink deposit is left unremoved). The increased wiping frequency of the single wiping member, as previously stated for example in Japanese Unexamined Patent Publications No. 2001-219567 and No. 2002-283590, can remove a firmly adhering substance only to some extent. It becomes necessary to improve the wiping operating force of the wiping member, which, however, will further increase the wiping frequency, causing such drawbacks as an easy-to-abrade wiping member, a shortened wiping member life, and consequently a deteriorated wiping effect.
Furthermore, setting the rubber hardness of the single wiping member within 40 to 60 degrees of A Hardness specified in JIS K6301 as stated in Japanese Unexamined Patent Publication No. Hei 9-76517, the wiping member will not be applicable to the case where a greater wiping operating force of the wiping member is needed. Furthermore, in Japanese Unexamined Patent Publication No. 2000-177113, although nearly the same wiping member operating force is adopted in accordance with the operating condition, application to a condition where the greater operating force of the wiping member is needed is not performed.